Metallic composition



& Rkm 9 m M 0 7, my 0 VH 6 mu 9n 0 n m Aug. 26, 1952 c H HACK ETAL METALLIC COMPOSITION Filed June 25, 1948 Patented Aug. 26, 1952 1 Earl n. Ha'ck, Flushing, 'N. y;,fana p H iCiborski, Mountain Lakes, N. 1'J, ;a'ssi g nfor's to ;National Lead Company, New York corporation of New Jersey 23 class. (01. 295mm) This invention relates -to a metallic com-posh =tion adapted for use 'as a bearing metal.

Tin base antifriction metal such as babbi-tt and lead base bearing metals of varying compositions have previously been widely used in the manufacture of smooth-surface bearings. Such alloys, which are relatively soft, possess properties which suit them for many bearing applications. However, they :are not particularly suited when high bearing pressures are encountered which :cond'ition necessitates "the employment of harderbearin'g metal. Efiorts to provide additional hardness in conventional alloys -by increasing the copper content thereof have been unsuccessful since copper does .not .form a solid solution with the other metal constituents when present in amounts greater than -a small proportion. For such application, the arthas adopted, among others, the so-called copper-lead" bearingmetal. "This composition eompriseslea'd and copper which are-melted together after which the 'resultingli'quidiis pouredinto molds to form bearing liners or otherwise fabricated, 'as desired. It is 'well known that if the copper content is not lower than'about 70%, the .lead and copper will bemiscible while :in the liquid phase,*even-though segregation "occurs :on solidification. This is not detrimental since the copper .forms the matrix "with the lead homogeneously dispersed throughout-it. The copper-lead bearhigso manufactured is, however, unfortunately "too :hard for many applications. The proportion. of copper is too high to obtain a bearing metal of desired 'antifriction properties and unless specially hardened shafts are used in conjunction therewith, scoring and other troubles may ensue. .Efforts to produce a :softer copper-lead alloy containing a lowerpercentage'of copper and lead results in separation :of the liquid .phases in the molten composition which makes impossible a homogeneous mixture. Thusgaagap exists in the.

hardness range of ordinary bearing I'metals between the hardest types of soft l antifriction metals and the softest copper-lead" compositions. A definite-need, however, exists for compositions having properties within this range; that is, equivalent in fatigue strength, jha-rdn'ess and otherdesirable characteristics 'towh'at would be ex ected from compositions containing irom about 10% to about 70% copper, for use in internal combustion engines, "particularly diesel engines in which bearing pressures greate'r than can be tolerated by "Babbitt metal are often encountered.

by proposing a ibearhi gyinetal consisting of a harder wire screen embedded in a sort conven- 't'ion'a'l' anti'friction composition :soh-asa suitable lead or tin ba'se'falloyj typical example {is a material eonsistine'tofa screen set Babbitt metal. "While it is .pos'sibleav ith such "a Structure to obtain the desired 'fhardness, such-composite structures as have liereto'forebeen proposed -have sufferedifromg'severalserious*disaevantages. The copper screenma'teri o'itenoont'aining aligned=copper particles-or areas. In a bearing surfacaa series maligned particles or a continuous "longitudinal: thread o'f copper wouldv cause serious "damage "to the shaft since the shaft in effect would jbefridin'g at thatsection on substantially 'copperpjlone.

It is, therefore; the object of invention to rovide ametallic compositionf'adapted ioruse as a bearing .fnietetl hayinghardness generally greater than the common ariti'fric't'ion metals such as Babbitt metal"but not having the-disadvantages of iC'OIIIPOSifiOnSfiflch-ES -"e'opperleaci alloy. It :is a further 'obiect'of'this invention'to provide a bearmg metal 'cmposl-tion- 'eontaining dispersed therein from 110%- tosibout 7o of-1a relatively hard metal:"orallm'. It is is; further object to provide suehwompoitions which'willibe stronger and possess better hearing seharacter- "istics than compositions heretotore proposed.and

of predetermined hardness. 'mhese iandfother objects "will become appareiit froin'the .following description. v

' In its broadest aspeetsithisi'invention c'ontemplates the provision oif' a-.imetallic composition which comprises 'a fakbria'oonsisti-ngiof interlaced loops 'of a relatively hard :metal or alloy thread '-'-thre'aii is used'tofo'rma :seri'esiofzinterlacedloops.

One or several layers bf-Esu'ch iabrie ma-y be employed'; if several faIBAlSBdT-TIBY rmaybe compressed-together z-t'o .:form"a zrelatively rigid, comp'ac't mass. The compacted frahric :strncture ,is

-then treatedwith molten jnntifriction metal so thatallitheintersticessorpores-therein are -fllled. The resulting:metallicrcompositionis adaptedior use as a bearing :metal and maybe. :formed or cast originally in suitable shapes adapted for use,

"The problem of supplying a fbe'ar 'ing of "proper hardness for such'applica'tions has been-attacked",-

or may be 'manufactured in'rt'he'fiormnf blocks The metallic composition of thlsfinvention'iwill ibein'g composedp'fstrands' I of 'relativeljystralg'ht f'se'ctlonsbfcopper o'rcopper alloy wire "has resulted in a Surface structure 4 v b q 3 become apparent from the annexed drawings in which Fig. 1 shows an example of a type of knit wire fabric adapted for this purpose. Fig. 2 shows a sectional end view of the fabric of Fig. 1 taken along the line 2-2. Fig. 3 shows a structure;formed;- compacting; under pressure several layers joffltlfeiknit fabric ofjFig. 1. shows a finished metallic composition showing the wire fabric embedded in an antifriction metal matrix.

Referring now to Fig. l, the fabric-is an open.

knit material of, for example, copper thread l which is mechanically and continuously formed into the interlocking or interlacedloops sub- .f

stantially as shown. Such a fabricis commer-l' 's cially most conveniently manufactured in the form of a continuous tube; sucha tube may be flattened to form two layers of fabric unbroken at the edges as will be evident. To make a compact structure containing a plurality of such layers; several sections'of' flattened tubing may be pressed together undersuitable high pressure .may be feadilyprbdiicdi 'When cupric metal thread is used" en eaqe'am altin' or 'lead base antifriction metal, the hardnessis' proportional to thecopperc nten'tand'a desirable range of characteristics 1 s obtained when the copper content ranges from aboutp.10% to 70% byivolume.

Such compositions provide bearing metals of hardnessgreater than conventional lead or tin base alloysand upto approximately the hardness of the so called" copper-lead.alloy. A preferred J composition providing adequate hardness for use under rigorous serviceiand possessing excellent v.,.antifriction and bearing propertiescontains from about 25% to 35% popper In order toobtainthedes iredcontent of wire -thread,.the type of fabric anddegree of compression may; be. selected to give a compacted thread structure of proper densities. To obtain highest density, -a;number of layers of close knit fabric of .finei -wire, ;preferably flat wire, are

pressed togetherfunder extreme pressure;

The type of fabricgemployed in the compositions of this invention may be originally knit so as to provide a fine,- close, or open mesh structure dependingon' the size of the individual inter-' laced loops and the diameter of the wire, Ordinarily, the mesh. is designated by the number of loops per inch and this may vary within wide limits according to requirements.

pressure employed vwill depend o nthe density required and: may vary from a. few pounds per square inch'when low densi'tycompacts are desired to' a numberofitons per square inch when compacted structuresof high density are necessary.. e

.To illustratethe manufacture of a-metallic composition of thiscinvention particularly adapted for use asza-bearing.liner,';the following exampl. is given. l 51 When several layers of such fabric are compressed together the Example I Four layers of knit-fabric of the type illustrated in Fig. 1 made of soft copper thread of .0011 inch diameter and having seven loops to the inch were compressed in a tubular shell using anexpandingamandrel. The pressure applied was equivalent to about 12004105. per square inch. The

resulting compacted structure, which contained 30% copper by volume, was then cleaned, fluxed with zinc chloride-ammonium chloride flux and then tinned by dipping in molten 30% tin 70% :lead. .The tinned compact while still hot was placedin asuitable mold and a lead base antifriction alloy-containing 5% antimony, 8.5% tin and the remainder lead was centrifugally cast into the mold to-fill the interstices in the copper thread compact. The resulting metallic composition contained the harder copper thread embedded in the softer antifriction matrix the cop- .per thread beingpresentin the amount of about 30% by volumepequivalent: to-- abo ut 25%; by weight. A machined surface-ofthecast composition showed copper areas dispersed through the softer metal showing, no -straight line geometric pattern. v a

The metal thread may be made of a metal characterized by suitable hardness and strength for the. purpose for;which the; metallic composition of this invention i-s ut ilized; For the manufacture of bearings: where eventh'e harder component of the. bearing composition should. be softer thanzthe shaft .material, .ac pr metal which is herein intended to include substantially pure copperas Well-as, alloys containingiamajor proportion of copper, including ibronzabrass and Monel metal: will be; suitable. In .addition,zsilver, aluminum andtheiralloys may.- be .used under 'partic'ularcondition .The-wire thread maybe of a diameter suited fo-r thepurpose of the composition and thetsize of: the article fabricated therefrom, and may ordinarily vary from 0.02 inch to very fine wire of 0.0001 inch or even. less. In the case vwhere bearings arev fabricated with only a thin layer .ofltheametallic composition in conjunction with a strongerlbackingmember, wire of fine diameter mayiadvantageously be employed to give utmost "dispersionof the-harder metal and best reinforcing characteristics. The wirethread may be of any suitable cross sectional shape;-

vL'Ihe antifriction metal which forms the matrix, may compriseany. relatively so'ftmetal or alloy having good bearing: characteristics as this term is used by those skilled in the art. The characteristics are generally .consideredtobe th ability to conform to irregularities in the shape or alignment of .the shaft'andito return readily to a smooth surface-after being cutx'or roughened-by foreign substances' whichmay. getsinto the Ibearing, low friction coefiic'ient and. suitable melting point. Conventional leadbase and tin baseantifriction alloysincluded withinthe generaliterm,

Babbitt metal; may be'employed. The. chief:- con- 'stituents'of such alloys are .tin, lead,: antimony and copper. :The ,alloys..commonly ,usedprange from, those having ahigh-percenta-ge of tin and small amounts of :copper and-antimony and no lead to those containing .a high percentage;- of lead; small amounts of copper and antimony and no. tin, those comprising predominantly tin being. nerally :known. astin base antifriction metals or tin-"bwe-Babbitts, and those comprising predominantly;lead 'being known as leadbase alloys of the same type. Pure lead issu itable, as

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alloys of suitable softnessjand quality.

It is desirable that the threads of the wire knit fabric and the matrix metal be firmly united to form a strong composition. Therefore, it may be desirable to coat the metal fabric with a suitable bonding metal prior to filling the pores or interstices of the fabric with the matrix metal. Thus,

persed in the matrix alloy. The .particular type of knit fabric employed results in an arrangement of the thread particles in the matrix metal characterized by the absence of any straight line pattern. Thus, the possibility of any section of the shaft riding for any appreciable arc of travel on the hard metal alone or on an aligned series of straight sections thereof is avoided. Such properties cannot be obtained by employment of conventional wire fabrics such as cloth or screen made by weaving straight threads. Furthermore, the knit fabric employed, when formed into fa compact by compressing several layers thereof, possesses marked unitary strength in the direction of its thickness as Well as other dimensions by reason of the penetration and interposition of the looped threads from the several layers. Structural reinforcement as well as the desired hardness is thereby imparted to the composition. Substantially greater fatigue strength, that is resistance to destructive effect of heavy alternating loads, is obained when the composition of this invention is used in a bearing compared to prior art alloys 0r compositions.

While this invention has been described and illustrated by the examples shown, it is not intended to be strictly limited thereto and other modifications and variations may be employed within the scope of the following claims.

We claim:

:1. A metallic composition, useful in a bearing, comprising a compact, formed from compressed layers of fabric formed of interlaced loops of a cupric metal thread of diameter from about 0.0001 to about 0.02 inch, said fabric having about 7 loops to the inch, embedded in'a matrix of a relatively soft antifriction metal so that a bearing surface formed from said composition will contain cupric metal portions interspersed between antifriction metal portions, said cupric metal portions being distributed to avoid linear, shaft scoring arrangement.

2. A metallic composition, useful in a bearing, comprising a compact, formed from compressed layers of fabric formed of interlaced loops of cupric metal thread of diameter from about 0.0001 to about 0.02 inch, said fabric having about 7 loops to the inch, embedded in a matrix of a relatively soft antifriction metal, said relatively hard metal thread being present in amount from about 10% to about by volume of the composition so that a bearing surface formed from said composition will contain cupric metal portions interspersed between antifriction metal portions, said cupric metal portions being distributed to avoid linear, shaft scoring arrangement.

3. A metallic composition, useful in a bearing, comprising a compact, formed from compressed layers of fabric formed of interlaced loops of copper thread of diameter from about 0.0001 to 7 about 0.02 inch, said fabric having about 7 loops to the inch, embedded in a matrix of a lead base antifriction metal, said copper thread being present in amount of between about 25% to 35% by volume of the composition so that a bearing surface formed from said composition will contain copper portions interspersed between lead base antifriction metal portions, said copper portions being distributed to avoid linear, shaft scoring arrangement.

CARL H. HACK.v JOHN M. CIBORSKI.

REFERENCES oI'rEn The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,280,909 Wales et a1. Oct. 8, 1918 1,779,771 Hartwell Oct. 28, 1930 2,212,473 Hessenbruch et al. Aug. 20, 1940 2,242,441 Shoemaker May 20, 1941 2,277,107 Imes Mar. 24, 1942 2,332,726 Joyce Oct. 26, 1943 2,357,578 Brownback Sept. 5, 1944 OTHER REFERENCES P. 588 Weld. Handbook 1942, pub. by Amer. Weld. Society, 33 W. 39th St., New York, N. Y. (Copy in Div. 14.)

P. 243 Engineer. Alloys by Norman Weldman, Ph. D. and Roger J. Metzler, pub. by American Society for Metals, 7301 Euclid Ave., Cleveland, Ohio. (Copy in Div. 14.) 

1. A METALLIC COMPOSITION, USEFUL IN A BEARING, COMPRISING A COMPACT, FORMED FROM COMPRESSED LAYERS OF FABRIC FORMED OF INTERLACED LOOPS OF A CUPRIC METAL THREAD OF DIAMETER FROM ABOUT 0.0001 TO ABOUT 0.02 INCH, SAID FABRIC HAVING ABOUT 7 LOOPS TO THE INCH, EMBEDDED IN A MATRIX OF A RELATIVELY SOFT ANTIFRICTION METAL SO THAT A BEARING SURFACE FORMED FROM SAID COMPOSITION WILL CONTAIN CUPRIC METAL PORTIONS INTERSPERSED BETWEEN ANTIFRICTION METAL PORTIONS, SAID CUPRIC METAL PORTIONS BEING DISTRIBUTED TO AVOID LINEAR, SHAFT SCORING ARRANGEMENT. 